如何返回“已经存在”？烧瓶不安的错误？ [英] How to return "already exists" error in Flask-restless?

问题描述

我想做一些异常处理程序。我在python中结合使用Flask-restless和SQLAlchemy。

I would like to do some handler for exception. I'm using a combination of Flask-restless and SQLAlchemy in python.

我的问题：

当我使用数据库中已经存在的对象向api发送请求时，SQLAlchemy显示异常：

When I send request to api with object that already exists in DB, SQLAlchemy shows exception:

IntegrityError: (IntegrityError) column <column_name> is not unique u'INSERT INTO ...

所以我尝试添加属性 validation_exceptions 转换为 create_api 方法：

So I have tried to add attribute validation_exceptions into create_api method:

manager.create_api( ... , validation_exceptions=[IntegrityError])

但是响应json包含：

But response json contains:

{
    "validation_errors": "Could not determine specific validation errors"
} 

并且服务器api显示异常：

and server api shows exception :

Traceback (most recent call last):
  File "C:\Python27\lib\site-packages\flask_restless\views.py", line 797, in _extract_error_messages
    left, right = str(exception).rsplit(':', 1)
ValueError: need more than 1 value to unpack

Flask-restless中的异常验证不适用于这种类型的异常（IntegrityError）

Exception validation in Flask-restless doesn't work with this type of exception (IntegrityError)

我该怎么办？可以为异常创建一些处理程序，并在json中返回我自己的错误消息吗？

What should I do? Is it possible to create some handler for exception and to return my own error message in json?

推荐答案

文档（迄今为止，该版本为v0.17.0）指出：

The documentation (v0.17.0 to date of this posting) states:

当前，Flask-Restless期望指定验证错误的实例具有errors属性，该属性是将字段名称映射为error的字典。描述（注：每个字段一个错误）。

Currently, Flask-Restless expects that an instance of a specified validation error will have a errors attribute, which is a dictionary mapping field name to error description (note: one error per field).

因此要更改 validation_errors 您的异常需要一个包含字典的错误属性。该词典的内容将在服务器响应中显示为 validation_errors 。

So to change the content of validation_errors your exception needs an errors attribute that contains a dictionary. The content of this dictionary will appear in the servers response as validation_errors.

来自 flask-restless / tests / test_validation.py ：

class TestSimpleValidation(ManagerTestBase):
"""Tests for validation errors raised by the SQLAlchemy's simple built-in
validation.
For more information about this functionality, see the documentation for
:func:`sqlalchemy.orm.validates`.
"""

def setup(self):
    """Create APIs for the validated models."""
    super(TestSimpleValidation, self).setup()

    class Person(self.Base):
        __tablename__ = 'person'
        id = Column(Integer, primary_key=True)
        age = Column(Integer, nullable=False)

        @validates('age')
        def validate_age(self, key, number):
            if not 0 <= number <= 150:
                exception = CoolValidationError()
                exception.errors = dict(age='Must be between 0 and 150')
                raise exception
            return number

        @validates('articles')
        def validate_articles(self, key, article):
            if article.title is not None and len(article.title) == 0:
                exception = CoolValidationError()
                exception.errors = {'articles': 'empty title not allowed'}
                raise exception
            return article

    class Article(self.Base):
        __tablename__ = 'article'
        id = Column(Integer, primary_key=True)
        title = Column(Unicode)
        author_id = Column(Integer, ForeignKey('person.id'))
        author = relationship('Person', backref=backref('articles'))

    self.Article = Article
    self.Person = Person
    self.Base.metadata.create_all()
    self.manager.create_api(Article)
    self.manager.create_api(Person, methods=['POST', 'PATCH'],
                            validation_exceptions=[CoolValidationError])

请求：

data = dict(data=dict(type='person', age=-1))
response = self.app.post('/api/person', data=dumps(data))

响应：

HTTP/1.1 400 Bad Request

{ "validation_errors":
    {
      "age": "Must be between 0 and 150",
    }
}

这篇关于如何返回“已经存在”？烧瓶不安的错误？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！